The present invention relates to a head rest for supporting the head of a user while sleeping and providing a positive air pressure (plenum) environment for respiration.
Continuous Positive Airway Pressure (CPAP) is a method of respiratory ventilation used primarily in the treatment of sleep apnea, for which it was first developed. CPAP ventilation is also commonly used for critically ill patients in hospital with respiratory failure, and in newborn infants (neonates). In these patients, CPAP ventilation can prevent the need for endotracheal intubation, or allow earlier extubation. Sometimes patients with neuromuscular diseases use this variety of ventilation as well. Often people with brain injury need these machines, as well as speech therapy to try to compensate for impaired use of the body, including the airway passages.
The CPAP machine was initially used mainly by patients for the treatment of sleep apnea at home, but now is in widespread use across intensive care units as a form of ventilation. Obstructive sleep apnea occurs when the upper airway becomes narrow as the muscles relax naturally during sleep. This reduces oxygen in the blood and causes arousal from sleep. The CPAP machine stops this phenomenon by delivering a stream of compressed air via a hose to a nasal pillow, nose mask or full-face mask, splinting the airway (keeping it open under air pressure) so that unobstructed breathing becomes possible, reducing and/or preventing apneas and hypopneas. It is the air pressure, and not the movement of the air, that prevents the apneas.
The CPAP machine blows air at a prescribed pressure (also called the titrated pressure). The necessary pressure is usually determined by a sleep physician after review of a study supervised by a sleep technician during an overnight study (polysomnography) in a sleep laboratory. The titrated pressure is the pressure of air at which most (if not all) apneas and hypopneas have been prevented, and it is usually measured in centimetres of water (cm H2O). The pressure required by most patients with sleep apnea ranges between 6 and 14 cm H2O. A typical CPAP machine can deliver pressures between 4 and 20 cm H2O. More specialized units can deliver pressures up to 25 or 30 cm H2O.
CPAP treatment can be highly effective in treatment of obstructive sleep apnea. For some patients, the improvement in the quality of sleep and quality of life due to CPAP treatment will be noticed after a single night's use. Often, the patient's sleep partner also benefits from markedly improved sleep quality, due to the amelioration of the patient's loud snoring. Given that sleep apnea is a chronic health issue, ongoing care is needed to maintain CPAP therapy.
A CPAP system commonly comprises a flow generator (CPAP machine) which provides the airflow, an interface (nasal or full face mask, nasal pillows, or less commonly a lip-seal mouthpiece) which provides the connection to the user's airway, and a hose which connects the flow generator (sometimes via an in-line humidifier) to the interface. Less commonly, CPAP systems may include a humidifier to add moisture to low humidity air. A heated water chamber can also be employed to increase user comfort by eliminating the dryness of the compressed air. The temperature can usually be adjusted or turned off to act as a passive humidifier if desired. In general, a heated humidifier is either integrated into the unit or has a separate power source (i.e. plug).
A ramp may be used to temporarily lower the pressure if the user does not immediately sleep. The pressure gradually rises to the prescribed level over a period of time that can be adjusted by the patient and/or the DME provider. Some devices are equipped with an exhalation pressure relief feature which causes a short drop in pressure during exhalation to reduce the effort required.
Most modern devices include data logging records for basic compliance info or detailed event logging, allowing the sleep physician (or patient) to download and analyze data recorded by the machine to verify treatment effectiveness.
Prospective CPAP candidates are often reluctant to use this therapy, since the nose mask and hose to the machine look uncomfortable and clumsy, and the airflow required for some patients can be vigorous. Some patients will develop nasal congestion while others may experience rhinitis or a runny nose. Some patients adjust to the treatment within a few weeks, others struggle for longer periods, and some discontinue treatment entirely.
CPAP manufacturers frequently offer different models at different price ranges, and CPAP masks have many different sizes and shapes, so that some users need to try several masks before finding a good fit. These different machines may not be comfortable for all users. Where the mask contacts the skin must be free from dirt and excess chemicals (such as skin oils). Shaving before mask-fitting may be necessary. These nuisances, as well as others, also prevent users from sleeping in the prone position.